# -*- coding: utf-8 -*-
#  @author  Bink
#  @date  2020/8/29 15:47
# @Email : 2641032316@qq.com


level = ['A', 'B', 'C', 'D', 'F']  # 100：A Plus
grades = range(1, 101)
mapper = {}
for x in level[:-1]:
    for grade in grades[-10::]:
        mapper[grade - 1] = x
    else:
        grades = grades[:-10]
else:
    for grade in grades:
        mapper[grade - 1] = (level[-1:].pop())
    mapper[100] = 'A Plus'
# print(mapper)

input_ch = input('输入一个分数，任意非数字字符退出：')
while input_ch.isdigit():
    input_ch = int(input_ch)
    if input_ch in mapper.keys():
        print(mapper[input_ch])
    else:
        print('tips：分数0~100')
    input_ch = input('输入一个分值：')
